KR20090081548A - ETCHING COMPOSITION FOR Al THIN LAYER AND Mo THIN LAYER, AND METHOD FOR FABRICATING METAL PATTERN USING THE SAME - Google Patents

Abstract

An etchant composite of an Mo thin film and an Al thin film and a metal pattern forming method using the same are provided to improve driving property of a liquid crystal display device by uniformly etching a large substrate and by not remaining residue. An etchant composite of an Mo thin film and an Al thin film includes phosphoric acid 50~76 weight%, nitric acid 2~10 weight%, acetic acid 2~15 weight%, sulfuric acid 0.1~5 weight%, univalent positive ion salt compound 0.1~5 weight%, and water 5~45.8 weight. The etchant composites of the single layer and the multilayer consist of one or more metals among aluminum metal and molybdenum metal. The water is the de-ionized water.

Description

 Etching liquid composition of Al thin film and Mo thin film and metal pattern formation method using the same {ETCHING COMPOSITION FOR Al THIN LAYER AND Mo THIN LAYER, AND METHOD FOR FABRICATING METAL PATTERN USING THE SAME}

The present invention relates to an etchant composition used for wet etching of a metal film, and more particularly, to an etchant composition for etching a single film and a multilayer film made of at least one metal of aluminum-based metal and molybdenum-based metal, and a metal pattern using the same. And a method for manufacturing an array substrate for a liquid crystal display device using the same.

Generally, flat panel display devices can be classified into active matrix and passive matrix according to the driving method, and active matrix liquid crystal display and active organic light emitting device Active Matrix Organic Light Emitting Device).

In addition, the active liquid crystal display and the active organic light emitting diode include a thin film transistor as a driving element, and the gate electrode, the gate wiring, the source / drain electrode, and the data wiring are molybdenum-based or aluminum-based metal. Depending on the configuration of the device, it may be formed of multiple metal layers of a single film or a double film or more.

Such a method of forming a multi-metal layer may include forming an insulating film, a semiconductor layer, and a photoresist using a metal film forming process by sputtering, a physical vapor deposition method, a plasma enhanced chemical vapor deposition method using plasma. The photoresist forming process in the selective area | region by application | coating, exposure, and image development, and an etching process, and the washing process before and after an individual unit process, etc. are included. More specifically, forming a gate electrode and a gate line, forming a gate insulating film on the gate electrode and the gate line, forming a semiconductor layer on the gate insulating film, source / drain electrodes and data on the semiconductor Forming a line, forming a protective insulating film on the source / drain electrodes and the data line, and forming a pixel electrode on the data protective insulating film.

An etching process for forming metal wirings during each process means a process of leaving a metal film in a selective region using a photoresist mask, and typically, dry etching using plasma or wet etching using an etching solution is used. .

For example, in the above process, the wet etching process requires an etching solution, and Application No. 10-1999-0041119 (Registration No. 10-0330582), previously filed by the present applicant, discloses a phosphoric acid-based powder etching solution, and includes phosphoric acid, nitric acid, and acetic acid. The Mo / Al-Nd double metal film was collectively etched by changing the composition ratio of.

However, the phosphoric acid-based etching solution reacts very sensitively to the wet etching characteristics of the metal wiring due to the viscosity of phosphoric acid and the physical properties of the etching equipment in the large flat panel display substrate. For example, in the TFT array substrate of a large liquid crystal flat panel display, the etching liquid depends on the conditions of the equipment due to the viscosity of phosphoric acid, and the etching characteristics of the etching liquid are partially uneven in the substrate. For example, a CD (Critical Dimension) skew (Skew) difference, a taper angle (Daper Angle) difference occurs, and the etching of the upper film protrusion in the double layer is generated as a stain in the substrate. Therefore, these defects present problems in the subsequent process, which is why they are not in line with recent trends that consider the efficiency of production and the operation and maintenance of equipment.

Therefore, the present invention can not only collectively etch single and multilayer films made of at least one metal of aluminum-based metals and molybdenum-based metals, but also an etching solution composition having excellent etching characteristics in etching uniformity and residue generation, and a metal pattern using the same. It is an object of the present invention to provide a method for forming a substrate and a method for manufacturing an array substrate for a liquid crystal display device using the same.

The present invention is 50 to 76% by weight phosphoric acid (H ₃ PO ₄ ), 2 to 10% by weight nitric acid (HNO ₃ ), 2 to 15% by weight acetic acid (CH ₃ COOH), sulfuric acid (H ₂ SO ₄ ) 0.1 to 5% by weight, monovalent cation salt compound An etching liquid composition of a single film and a multilayer film made of at least one metal of aluminum-based metal and molybdenum-based metal including 0.1 to 5% by weight and 5 to 45.8% by weight of water is provided.

In addition, the present invention

(i) forming a single film or a multilayer film made of at least one of an aluminum metal and a molybdenum metal on a substrate; And

(ii) it provides a method of forming a metal pattern comprising the step of etching the single layer or multilayer film formed in the etching liquid composition of the present invention.

In addition, the present invention

a) forming a gate electrode on the substrate;

b) forming a gate insulating layer on the substrate including the gate electrode;

c) forming a semiconductor layer on the gate insulating layer;

d) forming source and drain electrodes on the semiconductor layer; And

(e) forming a pixel electrode connected to the drain electrode;

At least one of the steps a) and d) is a step of forming a single film or a multilayer film made of at least one metal of an aluminum-based metal and a molybdenum-based metal, and etching the same with the etchant composition of the present invention to form each electrode. It provides a manufacturing method of an array substrate for a liquid crystal display device comprising the step of forming.

The edible liquid composition of the present invention can not only collectively etch single and multilayer films made of at least one metal of aluminum-based metals and molybdenum-based metals, but also exhibit excellent etching characteristics in etching uniformity and residue generation. Therefore, the etching process efficiency can be maximized.

In addition, even in the case of a large substrate, uniform etching is possible, and no residue is left, thereby improving driving characteristics of the liquid crystal display.

The present invention is 50 to 76% by weight phosphoric acid (H ₃ PO ₄ ), 2 to 10% by weight nitric acid (HNO ₃ ), 2 to 15% by weight acetic acid (CH ₃ COOH), sulfuric acid (H ₂ SO ₄ ) relates to an etching liquid composition of a single film and a multilayer film composed of at least one metal of aluminum metal and molybdenum metal containing 0.1 to 5% by weight, 0.1 to 5% by weight of a potassium salt compound, and 5 to 45.8% by weight of water. .

In the present invention, the aluminum-based metal and molybdenum-based metal are concepts including aluminum, molybdenum, and alloys thereof. In the present invention, a single film and a multilayer film made of at least one metal of an aluminum-based metal and a molybdenum-based metal have various forms. For example, in the case of Mo / Al-Nd double film, the molybdenum film is used as the upper film and the Al-Nd film is the lower film, or vice versa. In the case of the Mo-W / Al-Nd double film, the Mo-W alloy film is upper The Al-Nd alloy film is used as the lower film. In the case of Mo / Al / Mo, Mo / Al-Nd / Mo triple layer, the molybdenum film is used as the upper and lower films, and pure aluminum or Al-Nd film is used as the intermediate film. It is also used in the form of a single film such as Al, Al-Nd, Mo, Mo-W.

The etchant composition is characterized in that the batch etching of a single film and a multilayer film made of at least one metal of aluminum-based metal and molybdenum-based metal is possible.

Phosphoric acid as the main oxidizing agent in the etchant composition, the metal molybdenum-based and aluminum-based etching. The content of phosphoric acid is 50 to 76% by weight relative to the total weight of the composition. If the content of the phosphoric acid is less than 50% by weight the etching rate is low enough etching is not achieved, if the content of more than 76% by weight of the phosphoric acid due to the chemical wettability of the photoresist is a phenomenon that the end of the photoresist is dried up Lifting occurs in part, and this phenomenon accelerates the etching of the upper molybdenum-based metal in contact with the photoresist and causes a difference in side etch and taper angle with a part in which the lifting is not partially performed. This difference can be a problem as it occurs as a stain in subsequent processes.

In the etchant composition, nitric acid acts as an auxiliary oxidant, and serves to adjust the etching rate, side etch and taper angle together with phosphoric acid. The content of nitric acid is 2 to 10% by weight based on the total weight of the composition. When the content of nitric acid is less than 2% by weight, no etching or sufficient etching rate is not exerted, and when the content of the nitric acid is more than 10% by weight, a peeling phenomenon (peeling) occurs due to excessive lifting of the photoresist, resulting in a short circuit of the metal film. This occurs and the area of the metal film is reduced due to excessive etching, making it difficult to perform a role as an electrode.

Acetic acid in the etchant composition acts as a buffer to control the reaction rate and the like to control the decomposition rate of nitric acid, and generally serves to reduce the decomposition rate. The content of acetic acid is 2 to 15% by weight relative to the total weight of the composition. If the acetic acid content is less than 2% by weight, the uniformity of the TFT array substrate is lowered, and if the content of the acetic acid is more than 15% by weight, bubbles are generated by generating a lot of bubbles. In the array portion, sufficient etching may not be achieved by contact of bubbles.

Sulfuric acid in the etchant composition serves to control the etching rate, side etch and taper angle together with nitric acid as auxiliary oxidant. The content of sulfuric acid is from 0.1 to 5% by weight relative to the total weight of the composition. If the sulfuric acid content is less than 0.1% by weight, it does not function as an auxiliary oxidant for controlling the etching amount. When the amount of sulfuric acid is more than 5% by weight, overetching occurs with respect to molybdenum-based metal, resulting in non-uniform etching characteristics. It causes stains.

In the etchant composition, the monovalent cation salt compound serves as an etching inhibitor of molybdenum-based metal and aluminum-based metal to improve uniformity of etching in the substrate. The content of the monovalent cation salt compound is 0.1 to 5% by weight based on the total weight of the composition. If it is included in less than 0.1% by weight does not act as an etch inhibitor, when it exceeds 5% by weight rather than the etching rate of molybdenum-based metal and aluminum-based metal reduced Mo Tip in double or triple layer structure It can occur or cause etching residues, which can cause problems in subsequent processes.

In the etchant composition, the monovalent cation salt compound may be a compound known in the art without particular limitation, and specific examples thereof include ammonium salt, potassium salt and sodium salt. Examples of ammonium salts include NH ₄ NO ₃ , CH ₃ COONH ₄ , (NH ₄ ) ₂ SO ₄ , NH ₄ HSO ₄ , NH ₄ H ₂ PO ₄ , (NH ₄ ) ₂ HPO ₄ , and the like. KC ₂ H ₃ O ₂ , K ₂ CO ₃ , KClO ₃ , KCl, KF, KHSO ₄ , KNO ₃ , K ₂ C ₂ O ₄ , KClO ₄ , K ₂ O ₈ S ₂ , KH ₂ PO ₄ , K ₂ HPO ₄ , KBrO ₃ , KH ₂ C ₆ H ₅ O ₇ , KHCO ₂ , K ₂ SO ₄ , and the like. Examples of sodium salts include NaC ₂ H ₃ O ₂ , Na ₂ CO ₃ , NaClO ₃ , NaCl, and NaF. , NaHSO ₄ , NaNO ₃ , Na ₂ C ₂ O ₄ , NaClO ₄ , Na ₂ O ₈ S ₂ , NaH ₂ PO ₄ , Na ₂ HPO ₄ , NaBrO ₃ , NaH ₂ C ₆ H ₅ O ₇ , NaHCO ₂ , Na ₂ SO ₄ Etc. can be mentioned. Among these, potassium salt is especially preferable. The said monovalent cation salt compound can be used individually by 1 type or in mixture of 2 or more types.

 In the etchant composition, water is not particularly limited, but deionized water is preferable. In particular, it is more preferable to use deionized water having a specific resistance value of the water (that is, the degree of removal of ions in the water) of 18 kV / cm or more. The amount of water is included in an amount of 5 to 45.8% by weight based on the total weight of the composition, and the amount is the sum of the amount of water added alone and that included in other components added in the form of an aqueous solution.

In addition, the etchant composition according to the present invention may further include any additive conventionally used in the art to improve etching performance.

As the additive, a surfactant, a metal ion sequestrant, a corrosion inhibitor, a pH adjuster, or the like can be used.

The surfactant serves to lower the surface tension to increase the uniformity of the etching. Such surfactants are preferably surfactants that can withstand etching solutions and are compatible. Examples thereof include any anionic, cationic, zwitterionic or nonionic surfactant. Moreover, a fluorine-type surfactant can be used as surfactant.

The additive is not limited to this, but in order to further improve the effects of the present invention, various other additives known in the art may be selected and added.

In the etchant composition of the present invention, phosphoric acid (H ₃ PO ₄ ), acetic acid (CH ₃ COOH), sulfuric acid (H ₂ SO ₄ ), monovalent cation salt compounds can be prepared according to conventionally known methods, and in particular, semiconductor processes It is desirable to have a purity of the dragon.

The present invention also,

(i) forming a single film or a multilayer film made of at least one of an aluminum metal and a molybdenum metal on a substrate; And

(ii) a method of forming a metal pattern comprising etching the single or multi-layer film formed above with the etchant composition of the present invention.

In the method of forming the metal pattern, the step (i) includes providing a substrate and forming a single film or a multilayer film made of at least one metal of the aluminum-based metal and molybdenum-based metal on the substrate. . The substrate may be cleaned in a conventional manner, and a wafer, a glass substrate, a stainless steel substrate, a plastic substrate, or a quartz substrate may be used. As a method for forming a single film or a multilayer film made of at least one metal of an aluminum metal and molybdenum metal on the substrate, various methods known to those skilled in the art can be used, and the method is preferably formed by a vacuum deposition method or a sputtering method. .

In the step (ii), the photoresist is formed on the single film or the multilayer film formed in the step (i), the photoresist is selectively exposed using a mask, the exposed photoresist is bent, and the post The baked photoresist is developed to form a photoresist pattern. The single layer or the multilayer layer having the photoresist pattern is etched using the etching solution composition of the present invention to complete the metal pattern.

In addition, the present invention

a) forming a gate electrode on the substrate;

b) forming a gate insulating layer on the substrate including the gate electrode;

c) forming a semiconductor layer on the gate insulating layer;

d) forming source and drain electrodes on the semiconductor layer; And

(e) forming a pixel electrode connected to the drain electrode;

At least one of the steps a) and d) is a step of forming a single film or a multilayer film made of at least one metal of an aluminum-based metal and a molybdenum-based metal, and etching the same with the etchant composition of the present invention to form each electrode. The manufacturing method of the array substrate for liquid crystal display devices containing the process of forming is provided.

In the method of manufacturing an array substrate for a liquid crystal display device, the step a) may include a1) a single film made of at least one metal of aluminum-based metal and molybdenum-based metal on the substrate by vapor deposition or sputtering. Depositing a multilayer film; And a2) forming the gate electrode by patterning the single layer or the multilayer layer formed above with the etchant of the present invention. Here, the method of forming the single film or the multilayer film on the substrate is not limited only to the above examples.

In the method of manufacturing an array substrate for a liquid crystal display device according to the present invention, in the step b), silicon nitride (SiN _X ) is deposited on the gate electrode formed on the substrate to form a gate insulating layer. Here, the material used in forming the gate insulating layer is not limited to silicon nitride (SiN _x ), and the gate insulating layer may be formed using a material selected from various inorganic insulating materials including silicon oxide (SiO ₂ ). have.

In the method of manufacturing an array substrate for a liquid crystal display device according to the present invention, in the step c), a semiconductor layer is formed on the gate insulating layer by chemical vapor deposition (CVD). In other words, the active layer and the ohmic contact layer are sequentially formed and then patterned by dry etching. Here, the active layer is generally formed of pure amorphous silicon (a-Si: H), and the ohmic contact layer is formed of amorphous silicon (n ⁺ a-Si: H) containing impurities. Chemical vapor deposition (CVD) may be used to form the active layer and the ohmic contact layer, but is not limited thereto.

A method of manufacturing an array substrate for a liquid crystal display device according to the present invention, wherein step d) comprises: d1) forming source and drain electrodes on the semiconductor layer; And d2) forming an insulating layer on the source and drain electrodes. In step d1), a single film or a multilayer film made of at least one metal of aluminum metal and molybdenum metal is deposited on the ohmic contact layer by sputtering, and the source and drain electrodes are formed by etching with the etchant of the present invention. Here, the method of forming the one or a plurality of films on the substrate is not limited to those illustrated above. In step d2), an inorganic insulating group including silicon nitride (SiN _x ) and silicon oxide (SiO ₂ ) or a benzocyclobutene (BCB) and an acrylic resin are included on the source electrode and the drain electrode. The insulating layer may be formed of a single layer or a double layer by selecting from a group of organic insulating materials. The material of the insulating layer is not limited to only those exemplified above.

In the method of manufacturing an array substrate for a liquid crystal display device according to the present invention, in step e), a pixel electrode connected to the drain electrode is formed. For example, a transparent conductive material such as an indium tin oxide (ITO) or an indium zinc oxide (IZO) is deposited through a sputtering method and etched with an etchant composition according to the present invention to form a pixel electrode. The method of depositing the indium oxide film is not limited only to the sputtering method.

Hereinafter, the present invention will be described in more detail using examples and comparative examples. However, the following Examples and Comparative Examples are intended to illustrate the present invention, the present invention is not limited to the following Examples and Comparative Examples can be variously modified and changed.

Example  1 to 5: Etchant  Preparation of the composition and Etching characteristics  exam

A Mo / Al double layer and a Mo / Al / Mo triple layer substrate were prepared in a size of 550 × 650 mm, and 180 Kg of an etchant was prepared according to the composition ratios shown in Table 1. Etching liquid of Examples 1 to 5 prepared above were put into a spraying etching experiment apparatus (manufactured by SEMES, model name: ETCHER (TFT)) and warmed by setting the temperature to 40 ° C., and then the temperature was 40 ± 0.1 ° C. When reached, an etching process was performed. Total Etch Time was performed by giving 40% Over Etch to Mo / Al and Mo / Al / Mo substrates based on EPD (End Point Detection). After removal, the resultant was washed with deionized water, dried using a hot air drying device, and removed from the photoresist using a photoresist stripper. After washing and drying, the etching profile was evaluated by using an electron scanning microscope (SEM; manufactured by HITACHI, model name: S-4700) with an inclination angle, one-sided CD (critical dimension) loss, and etching residue. The results are shown in Table 1.

<Etch Characteristic Criteria>

◎: no etching residue, one side CD loss≤0.5㎛, taper angle (Gate: 30 ~ 50 degree, Data: 50 ~ 70 degree)

○: No etching residue, one side CD loss ≤0.7㎛, taper angle (Gate: 30 ~ 50 degree, Data: 50 ~ 70 degree)

△: no etching residue, one side CD loss ≥1.0㎛, taper angle (Gate: Mo Tip, Data: 50 ~ 70 degrees)

×: partial Unetch, gate upper Mo over etch, data lower Mo undercut ≧ 0.1 μm,

From the results described in Table 1, it can be seen that the etching liquid composition according to the present invention has excellent etching characteristics with respect to Mo / Al double layer and Mo / Al / Mo triple layer substrates. In addition, it can be seen that the etching solution of Example 2 and Example 7 shows the best performance among these.

SEM images taken after the Mo / Al double layer was etched using the etchant composition of Example 2 were attached to FIG. 1A. In addition, SEM images taken after the Mo / Al / Mo triple layer was etched using the etchant composition of Example 7 were attached to FIG. 1B.

Comparative example  1 to 3: Etchant  Preparation of the composition and Etching characteristics  exam

 180 kg of an etchant was prepared according to the composition ratios shown in Table 2, and the etching characteristics were tested in the same manner as in the above example. The results are shown in Table 2.

As can be seen in Table 2, Comparative Example 1 and Comparative Example 4 is an over-oxidation of the Mo layer in the resulting Mo / Al thin film and Mo / Al / Mo thin film containing an excess amount (7% by weight) sulfuric acid as an auxiliary oxidant Phenomenon occurred and poor etching properties were observed.In the etching solution compositions of Comparative Examples 2 and 5, an excessive amount (6% by weight) of potassium salt resulted in Mo Tip on all substrates. In Example 6, too little (1.5% by weight) of nitric acid, an auxiliary oxidant, resulted in unetch and residue.

SEM images taken after the Mo / Al double layer was etched using the etchant composition of Comparative Example 2 were attached to FIG. 2A. In addition, the SEM photograph taken after etching the Mo / Al / Mo triple layer using the etchant composition of Comparative Example 4 was attached to Figure 2b.

1A is a SEM photograph after etching a Mo / Al double layer using the etchant composition of Example 2,

FIG. 1B is a SEM photograph after etching Mo / Al / Mo triple layer using the etchant composition of Example 7.

2A is a SEM photograph after etching the Mo / Al double layer using the etchant composition of Comparative Example 2,

Figure 2b is a SEM photograph after etching the Mo / Al / Mo triple layer using the etchant composition of Comparative Example 4.

Claims (10)

50 to 76 wt% phosphoric acid (H ₃ PO ₄ ), 2 to 10 wt% nitric acid (HNO ₃ ), 2 to 15 wt% acetic acid (CH ₃ COOH), sulfuric acid (H ₂ SO ₄ ) 0.1 To 5% by weight, monovalent cation salt compound An etching liquid composition of a single film and a multilayer film made of at least one metal of aluminum-based metal and molybdenum-based metal containing 0.1 to 5% by weight, and 5 to 45.8% by weight of water. The monovalent cation salt compound of claim 1, wherein the monovalent cation salt compound comprises at least one selected from the group consisting of ammonium salt compounds, potassium salt compounds, and sodium salt compounds. Etch solution compositions of membranes and multilayers. The etchant composition according to claim 2, wherein the monovalent cation salt compound is at least one selected from the group consisting of calcium salt compounds and at least one metal selected from the group consisting of aluminum-based metals and molybdenum-based metals. The method of claim 3, wherein the potassium salt compound is KC ₂ H ₃ O ₂ , K ₂ CO ₃ , KClO ₃ , KCl, KF, KHSO ₄ , KNO ₃ , K ₂ C ₂ O ₄ , KClO ₄ , K ₂ O ₈ S ₂ , KH ₂ PO ₄ , K ₂ HPO ₄ , KBrO ₃ , KH ₂ C ₆ H ₅ O ₇ , KHCO ₂ , and K ₂ SO ₄ characterized by consisting of at least one metal of the aluminum-based metal and molybdenum-based metal Etch liquid composition of a single film and a multilayer film. The etchant composition according to claim 1, wherein the water is deionized water. The single layer and multilayer membranes are formed of at least one of an aluminum-based metal and a molybdenum-based metal. The method of claim 1, wherein the single film and the multilayer film made of at least one metal of the aluminum-based metal and molybdenum-based metal further comprises at least one additive selected from surfactants, metal ion blocking agents, corrosion inhibitors and pH adjusting agents. Etchant composition. Forming a single film and a multilayer film made of at least one of an aluminum metal and a molybdenum metal on a substrate; And A method of forming a metal pattern comprising etching a single layer or a multilayer formed in the etching liquid composition of any one of claims 1 to 6. The method of claim 7, further comprising forming a photoresist pattern on the formed single layer or the multilayer layer. a) forming a gate electrode on the substrate; b) forming a gate insulating layer on the substrate including the gate electrode; c) forming a semiconductor layer on the gate insulating layer; d) forming source and drain electrodes on the semiconductor layer; And (e) forming a pixel electrode connected to the drain electrode; Any one or more of steps a) and d) is a step of forming a single film or a multi-layer film consisting of at least one metal of aluminum-based metal and molybdenum-based metal and the etching liquid composition of any one of claims 1 to 6. A method of manufacturing an array substrate for a liquid crystal display device comprising the step of etching to form respective electrodes. 10. The method of claim 9, wherein the array substrate for liquid crystal display device is a thin film transistor (TFT) array substrate.

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